The present invention relates to electrical connectors and more particularly to cam operated, multicontact, zero insertion force connectors utilizing shape memory metals to actuate the cam mechanism.
The prior art provides two basic types of cam operated, multicontact, zero insertion force connectors; connectors employing lever operated translating cams and lever operated rotating cams. In both of these types of mechanisms opposed pairs of contacts are pushed apart when the cam is actuated by action of the associated lever and are permitted to return towards a closed position when the cam is returned to its quiescent position. When the contacts are separated a printed circuit board may be inserted with zero insertion force and is tightly clamped between the contacts when the contacts are released.
In the translatable cam operator type, an elongated structure has a long slide disposed along each side of the elongated body. The body has two rows of closely spaced electrical contacts, with each row located in an array parallel to and inwardly of one of the slides. A contact in each row has a contact in the other row opposed thereto with each being located in a common plane perpendicular to the elongated dimension of the body.
In the unactuated condition, the opposed contacts of each row are closely spaced in the transverse planes such as to rest firmly against contacts located on opposite sides of a printed circuit board or the like located in the connector. The board is held firmly in place.
When a board is to be withdrawn or inserted, the slides are translated, and cams carried thereon cause the opposed contacts to be spread to a spacing greater than the thickness of the board. Thus, a board may be inserted or withdrawn essentially without contact between the board and connector.
A rotatable cam actuator lies along the center line of the connector and upon rotation pushes up a bail that pushes the opposed contacts apart.
In both types of lever actuated cams, large amounts of space must be provided for movement of the lever and the levers must be located such that an operator can get his hand or a tool to the lever to operate it. In electronic equipment using large numbers of these connectors such as computers, telecommunications equipment and other complex electronic equipment, the space and accessibility requirements impose restrictions on the use of such connectors or where used on the geometry of the equipment.
On the other hand, the basic concepts of the connectors are valid and are written into the specifications for numerous equipment lines currently in production by numerous original equipment manufacturers. Thus, if such connectors can be improved by a change only in the cam actuator, a large market for such a device is already in place, especially if the modified device provides fail safe operation.